human-repr 0.4.0

Generate beautiful human representations of bytes, durations and even throughputs!
Documentation

human-repr

Generate beautiful human representations of bytes, durations and even throughputs!

License: MIT Crates.io Docs

What it does

Easily generate human-readable descriptions directly on primitive numbers, of several kinds:

  • counts, supporting SI prefixes k, M, G, T, P, E, Z, and Y (optional IEC and "mixed" ones, see Rust features);
  • durations, supporting nanos (ns), millis (ms), micros (µs), seconds (s), and even hour-minute-seconds (HH:MM:SS);
  • throughputs, supporting per-day (/d), per-hour (/h), per-minute (/m), and per-second (/s).

It does not use any dependencies, is well-tested, and is blazingly fast, taking only ~50 ns to generate a representation! (criterion benchmarks inside) In the new version 0.4, it even does not allocate Strings anymore! I've returned structs that implement [std::fmt::Display], so you can now print them with no heap allocations at all! And if you do need the String, a simple .to_string() will do 😜

They work on all Rust primitive number types: u8, u16, u32, u64, u128, usize, f32, f64, i8, i16, i32, i64, i128, isize.

The unit parameter some methods refer to means the entity you're dealing with, like bytes, actions, iterations, errors, whatever! Just send that text, and you're good to go! Bytes have dedicated methods for convenience.

Examples

use human_repr::HumanRepr;

// counts (bytes or anything)
assert_eq!("43.2 MB", 43214321_u32.human_count_bytes());
assert_eq!("123.5 kPackets", 123456_u64.human_count("Packets"));

// durations
assert_eq!("15.6 µs", 0.0000156.human_duration());
assert_eq!("10 ms", 0.01.human_duration());
assert_eq!("1:14:48", 4488.395.human_duration());

// throughputs (bytes or anything)
assert_eq!("1.2 MB/s", (1234567. / 1.).human_throughput_bytes());
assert_eq!("6.1 tests/m", (10. / 99.).human_throughput("tests"));
assert_eq!("9 errors/d", (125. / 1200000.).human_throughput("errors"));

How to use it

Add this dependency to your Cargo.toml file:

human-repr = "0"

Use the trait:

use human_repr::HumanRepr;

That's it! You can now call on any number:

# use human_repr::HumanRepr;
# let num = 123;
num.human_count("unit");
num.human_count_bytes();

num.human_duration();

num.human_throughput("unit");
num.human_throughput_bytes();

Rust features:

According to the SI standard, there are 1000 bytes in a kilobyte. There is another standard called IEC that has 1024 bytes in a kibibyte, but this is only useful when measuring things that are naturally a power of two, e.g. a stick of RAM.

Be careful to not render IEC quantities with SI scaling, which would be incorrect. But I still support it, if you really want to ;)

By default, human-repr will use SI with 1000 divisor, and the prefixes: k, M, G, T, P, E, Z, and Y. You can modify this by enabling optional features:

  • iec => use IEC instead of SI: Ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi (implies 1024)
  • 1024 => use 1024 divisor, but if iec is not enabled, use prefixes: K, M, G, T, P, E, Z, and Y (note the upper 'K')
  • nospace => remove the space between values and scales/units everywhere: 48GB instead of 48 GB, 15.6µs instead of 15.6 µs, and 12.4 B/m instead of 12.4 B/m

The human duration magic

I've used just one key concept in designing the human duration features: cleanliness.

3.44 s is more meaningful than 3.43584783784 s, and 14.1 µs is much, much nicer than .0000141233333 s.

So what I do is: round values to at most two decimal places (larger scales have more decimals), and find the best scale to represent them, minimizing resulting values smaller than 1. The search for the best scale considers even the rounding been applied!

0.000999999 does not end up as 999.9 µs (truncate) nor 1000.0 µs (bad scale), it is auto-upgraded to the next one 1.0 ms!

The human duration scale changes seamlessly from nanoseconds to hours!

  • values smaller than 60 seconds are always rendered as D.D[D] scale, with one or two decimals;
  • .0 and .00 are efficiently not generated (no trim followed by to_owned for example), it is handled directly in the format arguments;
  • from 1 minute onward it changes to "H:MM:SS".

The human throughput magic

I've made the human throughput with a similar logic. It is funny how much trickier "throughput" is to the human brain!

If something took 1165263 seconds to handle 123 items, how fast did it go? It's not obvious...

It doesn't help much even if we divide the duration by the number of items: 9473 seconds/item still does not seem that good. How fast was that? We can't say for sure. Humm, how many items did we do per time?

Oh, we just need to invert it, so 0.000105555569858 items/second, there it is! 😂

To make some sense of it we now need to multiply that by 3600 (seconds in an hour) to get 0.38 per hour, which is much better, and again by 24 (hours in a day) to finally get 9.12 per day!! Now we know how fast that process was! \o/ As you see, it's not easy at all for our brains to estimate that...

The human throughput scale changes seamlessly from per-second to per-day!

  • .0 and .00 are efficiently not generated too, much like the duration magic;
  • it also automatically inserts SI prefixes when in the fastest scale /second, so we get 2.4 MB/s or 6.42 Gitems/s 👍

The human count magic

Oh, this is the simplest of them all! I just continually divide by the divisor (1000 or 1024), until the value gets smaller than it. No funny business like logs or exponentials at all.

Rounding is also handled so there's no truncation or bad scale, the number of decimals also increase the larger the scale gets, and .0 and .00 are also never generated.

Changelog highlights

  • 0.3.x Jun 01, 2022: support for a new group of prefixes for 1024 only (without iec)
  • 0.2.x Jun 01, 2022: more flexible API (impl AsRef<str>), greatly improved documentation
  • 0.1.x Jun 01, 2022: first release, include readme, method and module docs, describe features already implemented

License

This software is licensed under the MIT License. See the LICENSE file in the top distribution directory for the full license text.

Maintaining an open source project is hard and time-consuming, and I've put much ❤️ and effort into this.

If you've appreciated my work, you can back me up with a donation! Thank you 😊